$ git clone -n https://src.fedoraproject.org/rpms/rust-num.git /var/lib/mock/f45-build-43447-803/root/chroot_tmpdir/scmroot/rust-num
Cloning into '/var/lib/mock/f45-build-43447-803/root/chroot_tmpdir/scmroot/rust-num'...
$ git fetch origin 4e356a7a6453a35d3c755b1da34a7a359d393ab7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-num
 * [new ref]         4e356a7a6453a35d3c755b1da34a7a359d393ab7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4e356a7 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild